The present disclosure relates to a magnetic rail brake device of a rail vehicle including at least one braking magnet. The at least one braking magnet includes a magnet coil body, on which a plurality of magnetic magnet elements are held such that they can move. Also included is at least one fixing strip, which runs parallel to the longitudinal extent of the magnet coil body and is directly connected to said magnet coil body, for the purpose of fixing the braking magnet to further components of the magnetic rail brake device.
A magnetic rail brake is described, for example, in DE 101 11 685 A1. The force-generating main component of an electrical magnetic rail brake is the braking magnet. In principle, it is an electromagnet, comprising a magnet coil extending in the rail direction and a magnet core, which is similar to a horseshoe and forms the base or carrier body. The direct current flowing in the magnet coil brings about a magnetic voltage, which induces a magnetic flux in the magnet core, which magnetic flux is short-circuited via the rail head as soon as the braking magnet rests on the rail. As a result, a magnetic attraction force is brought about between the braking magnet and the rail. Owing to the kinetic energy of the moving rail vehicle, the magnetic rail brake is pulled along the rail via drivers. In this case, a braking force is produced owing to the sliding friction between the braking magnet and the rail in conjunction with the magnetic attraction force. The extent of the braking force of a magnetic rail brake is dependent, inter alia, on the reluctance of the magnetic circuit, i.e. the geometry and permeability, the current linkage, the friction value between the braking magnet and the rail and the rail state.
In relation to the embodiments of magnetic rail brakes, reference is also made to the publication “Grundlagen der Bremstechnik” [Fundamentals in braking technology], pages 92 to 97 by Knorr-Bremse AG, Munich, 2003.
In principle, it is possible to distinguish between two different types of magnets in terms of their structural design. In a first embodiment, the braking magnet is a rigid magnet, to which two wearing strips are screwed which are separated by a nonmagnetic strip in the longitudinal direction. This serves the purpose of avoiding a magnetic short circuit within the braking magnet. Rigid magnets are usually used for local transport in streetcar systems and city railroads.
Furthermore, generic link magnets are known, in the case of which the magnet coil body does not have a continuous, rigid steel core, but has open chambers split off between the steel cores merely by partition walls. Magnet elements are inserted into the individual chambers and can move during the braking process. It is thus possible for them to follow uneven sections on the rail head. Link magnets are used as standard in the standard-gage railroad sector. In the case of known link magnets, at least one fixing strip, which runs parallel to the longitudinal extent of the magnet coil body and is directly connected to said magnet coil body, can be provided for the purpose of fixing the braking magnet to further components of the magnetic rail brake device, such as to track holders or to flanges of actuating cylinders, for example. In this case, the track holders or flanges of the actuating cylinders may result in magnetic short circuits, which disadvantageously reduce the holding force of the link magnets on the rail.
In contrast, the present disclosure relates to a magnetic rail brake device such that it produces a braking power which is as high as possible given a simple design and with low manufacturing costs.
The magnetic rail brake device of the present disclosure comprises a fixing strip that includes a diamagnetic or paramagnetic material.
A diamagnetic material is generally understood to be a material whose relative permeability is less than 1 and which weakens the magnetic field. Such a material may be, for example, silver or copper. Paramagnetic materials have a relative permeability of slightly greater than 1 and increase the magnetic field slightly. Such a material may be, for example, aluminum, platinum or air. In terms of their effect on the magnetic field, these materials differ markedly from ferromagnetic materials such as iron, cobalt, nickel, for example, which considerably intensify the magnetic field.
Owing to the fact that the present disclosure provides for the fixing strip to include a diamagnetic or paramagnetic material, this causes the magnetic field to be weakened or only slightly intensified, with the result that the magnetic stray flux on the magnet coil body is markedly reduced in comparison with a fixing strip consisting of a ferromagnetic material. The diamagnetic or paramagnetic material brings about an advantageously high magnetic holding force. The fixing strip therefore fulfills an advantageous dual function in that, on the one hand, it holds the magnet coil body on the attachment parts and, on the other hand, contributes to the avoidance of magnetic short circuits brought about thereby. As a result, no additional separating bodies including a diamagnetic or paramagnetic material are required.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.